WO2014044041A1

WO2014044041A1 - Solid-state lithium ion battery composite electrode material, its preparation method and solid-state lithium-ion battery

Info

Publication number: WO2014044041A1
Application number: PCT/CN2013/073503
Authority: WO
Inventors: 裴佳宁
Original assignee: 华为技术有限公司
Priority date: 2012-09-18
Filing date: 2013-03-29
Publication date: 2014-03-27
Also published as: CN103682354A; CN103682354B

Abstract

Embodiment of the present invention provides a solid-state lithium ion battery electrode composite material comprising an electrode active material and a coating layer provided on the surface of the electrode active material, wherein the material of the coating layer comprising by weight: polymer formed of 0.1-20 parts of polymer monomer and 0.1-50 parts of ethylene glycol derivative, 0.1 to 10 parts of lithium salt, 0.1 to 10 parts of a polymerization initiator, 50 to 99.9 parts of a plasticizer, wherein the polymer monomer is selected from one or several monomers of fluorine-containing polymer monomer, ether polymer monomer, acrylic polymer monomer and acrylonitrile polymer monomer. The coating layer can effectively suppress the formation of space charge layer; reduce interface resistance of the solid-state lithium ion battery, thereby improving solid-state battery cycle stability and durability. Embodiments of the present invention also provide a preparation method of the solid-state lithium ion battery electrode material composite, and solid-state lithium-ion batteries comprising the composite electrode material.

Description

All-solid-state lithium ion battery composite electrode material and preparation method thereof and all-solid-state lithium ion battery The application claims to the Chinese Patent Office on September 18, 2012, application number 201210345669.5, the invention name is "an all-solid lithium battery" The ionic battery composite electrode material and its preparation method and the all-solid-state lithium ion battery are entitled to the priority of the Chinese patent application, the entire contents of which are hereby incorporated by reference. Technical field

The present invention relates to the field of lithium ion batteries, and in particular to an all-solid lithium ion battery composite type electrode material, a preparation method thereof and an all-solid lithium ion battery. Background technique

Since the 1990s, lithium-ion batteries have attracted close attention in many energy-replacement products due to their high energy density, good cycle performance, and no memory effect.

In recent years, with the increasing demand for battery applications for electric vehicles and large-scale stationary equipment storage batteries, all-solid-state lithium-ion batteries with safety and long life have begun to attract attention, and their use of incombustible solid inorganic substances as electrolytes is not only high. The energy density has the advantages of good safety and stability, simple installation device and low manufacturing cost.

At present, most of the inorganic solid electrolytes mainly studied and applied are concentrated on oxide-and-stone-related materials. Compared with oxides, sulfides are favored by researchers because of their excellent ionic conductivity. However, a common problem in the application of a sulfide solid electrolyte is that at the electrode/solid electrolyte interface, a sulfide solid electrolyte having a chalcogen element represented by crosslinked sulfur easily reacts with an electrode active material to decompose, thereby forming a space. The charge layer causes a high impedance to the movement of lithium ions at the interface between the electrode/solid electrolyte, resulting in a battery with lower output power, lower durability and Ring performance. Summary of the invention

In view of this, the first aspect of the embodiments of the present invention provides an all-solid lithium ion battery composite electrode material, which solves the problem that the stone dangerous solid electrolyte easily decomposes by reacting with the electrode active material, thereby forming a space charge layer and making the electrode/solid state The high impedance of lithium ion movement at the interface between the electrolytes results in a battery with lower output power, lower durability and cycle performance problems. A second aspect of the embodiments of the present invention provides a method for preparing an all-solid lithium ion battery composite electrode material. A third aspect of the embodiments of the present invention provides an all-solid lithium ion battery.

In a first aspect, an embodiment of the present invention provides an all-solid lithium ion battery composite electrode material, comprising an electrode active material and a coating layer disposed on a surface of the electrode active material, wherein the electrode active material is a positive electrode active material or The negative electrode active material, the material of the coating layer comprises, by weight: 0.1 to 20 parts of a polymer monomer and 0.1 to 50 parts of a polymer of a glycol derivative, 0.1 to 10 parts of a lithium salt, 0.1 to 10 parts of a polymerization initiator and 50 to 99.9 parts of a plasticizer, the polymer monomer being selected from the group consisting of a fluorine-based polymer monomer, an ether polymer monomer, an acrylic polymer monomer, and an acrylonitrile polymer monomer One or several of them.

Compared with the prior art, the all-solid lithium ion battery composite electrode material provided by the present invention has a coating layer, which is coated as an interface modification layer on the surface of the electrode active material, and is not combined with the electrode active material. Reacts with a solid electrolyte. The coating layer coated on the surface of the electrode active material in the present invention can effectively inhibit the sulfide solid electrolyte S ₃ PS-SP ₃ center structure in an all-solid lithium ion battery as an intermediate layer of an electrode active material and a solid electrolyte. The crosslinked sulfur reacts with the electrode active material to decompose, suppresses the formation of the space charge layer, and suppresses the formation of high interfacial impedance, thereby not reducing the conductivity of lithium ions. The all-solid-state lithium-ion battery composite electrode material ultimately enables the battery to have a high output power, and has good durability and cycle stability. Preferably, the fluorine-based polymer monomer is vinylidene fluoride and/or vinylidene fluoride-hexafluoropropylene, and the ether polymer monomer is ethylene oxide and/or propylene oxide, and the acrylic polymer monomer It is a decyl acrylate.

Preferably, the ethylene glycol derivative is one or more selected from the group consisting of ethylene glycol monodecyl acrylate, ethylene glycol dimercapto acrylate, ethylene glycol acrylate, and ethylene glycol diacrylate.

Preferably, the lithium salt is selected from the group consisting of lithium perchlorate LiC10 ₄ , lithium tetrafluoroborate LiBF ₄ , lithium hexafluorophosphate LiPF ₆ , lithium hexafluoroarsenate LiAsF ₆ , lithium trifluoroantimonate LiCF ₃ S0 ₃ and bistrifluorofluorenyl One or more of lithium sulfonylamide LiN(CF ₃ S0 ₂ ) ₂ .

Preferably, the polymerization initiator is one or more selected from the group consisting of azobisisobutyronitrile, benzoyl peroxide, acetyl peroxide and dibenzophenone.

Preferably, the plasticizer is selected from one or more of propylene carbonate, dinonyl carbonate, diethyl carbonate, ethyl ruthenium carbonate and ethylene carbonate.

Preferably, the material of the coating layer further comprises 0.1 to 30 parts of an additive selected from the group consisting of nano-SiO ₂ , nano-Ti0 ₂ , nano-A1 ₂ 0 ₃ , single-walled carbon nanotubes, multi-walled carbon nanotubes, One or more of zeolite, montmorillonite and molecular sieve ZSM-5.

Preferably, the positive electrode active material is selected from one or more of lithium cobaltate, lithium nickelate, lithium manganate, lithium iron phosphate, lithium nickel cobalt manganese oxide, vanadium pentoxide, molybdenum trioxide and titanium disulfide.

Preferably, the anode active material is selected from one or more of graphite, hard carbon, silicon, silicon oxide, tin alloy, lithium cobalt nitride, lithium metal, and lithium alloy.

Preferably, the thickness of the coating layer is from 0.1 to 2000 nm. More preferably, the thickness of the coating layer is from 0.1 to 1000 Å.

Preferably, the side of the coating layer away from the electrode active material does not contain an electrode active material.

The all-solid lithium ion battery composite electrode material provided by the first aspect of the present invention can effectively inhibit the occurrence of cross-linked sulfur and electrode active materials in the central structure of the sulfide solid electrolyte S ₃ PS-SP _{3 .} Decomposes by reaction, suppresses formation of a space charge layer, suppresses formation of high interfacial impedance, thereby not reducing lithium ion conductivity; further, the coating layer does not hinder lithium ion between the electrode active material and the solid electrolyte Conduction; therefore, the all-solid-state lithium-ion battery composite electrode material ultimately enables the battery to have a higher output power, with good durability and cycle performance.

In a second aspect, an embodiment of the present invention provides a method for preparing an all-solid lithium ion battery composite electrode material, including the following steps:

0.1 to 20 parts by weight of the polymer monomer, 0.1 to 50 parts of the ethylene glycol derivative, 0.1 to 10 parts of the lithium salt, 0.1 to 10 parts of the polymerization initiator, and 50 to 99.9 parts of the plasticizer are prepared. a mixed solution, the polymer monomer being selected from one or more of a fluorine-based polymer monomer, an ether polymer monomer, an acrylic polymer monomer, and an acrylonitrile polymer monomer;

The mixed solution is disposed by electrospinning, electroblowing, liquid phase spraying or printing on the surface of the electrode active material by thermal polymerization, electron beam polymerization or ultraviolet polymerization to form a coating. Layer, an all-solid lithium ion battery composite electrode material is obtained.

Preferably, the fluorine-based polymer monomer is vinylidene fluoride and/or vinylidene fluoride-hexafluoropropylene, and the ether polymer monomer is ethylene oxide and/or propylene oxide, and the acrylic polymer monomer It is a decyl acrylate.

Preferably, the polymerization initiator is one or more selected from the group consisting of azobisisobutyronitrile, benzoyl peroxide, acetyl peroxide, and benzophenone. Preferably, the plasticizer is selected from one or more of propylene carbonate, dinonyl carbonate, diethyl carbonate, ethyl ruthenium carbonate and ethylene carbonate.

Preferably, the process of formulating the mixed solution further comprises adding 0.1 to 30 parts of an additive selected from the group consisting of nano-SiO ₂ , nano-TiO ₂ , nano-A _{1 2} 0 ₃ , single-walled carbon nanotubes, multi-layer carbon nanometers. One or more of tube, zeolite, montmorillonite and molecular sieve ZSM-5.

The preparation method of the all-solid lithium ion battery composite electrode material provided by the second aspect of the present invention is simple and easy, and the integrated solid-state lithium ion battery composite electrode material can improve the electrode/solid electrolyte interface and reduce lithium ion. The impedance that moves between the electrode active material and the solid electrolyte, so that the all-solid-state lithium ion battery has a high output power, and has good durability and cycle performance.

In a third aspect, an embodiment of the present invention provides an all-solid-state lithium ion battery, including a positive electrode, a negative electrode, and a sulfide-based solid electrolyte, wherein the positive electrode or the negative electrode includes the all solid state provided by the first aspect of the embodiment of the present invention. Lithium-ion battery composite electrode material.

Preferably, the sulfide-based solid electrolyte of sulfide Li ₂ S and Li ₂ S in addition to the composition, the molar ratio of sulfide Li ₂ S and Li ₂ S other than 50: 50~95: 5 .

Preferably, the sulfide-based solid electrolyte has a powder particle size of 0.5 μηη! ~ 5μηι, more preferably, the particle size is 0.5μη! ~ 1μηι. Preferably, the sulfide other than Li ₂ S is SiS ₂ , P ₂ S ₅ , B ₂ S ₃ , GeS ₂ , Sb ₂ S ₃ , ZrS _x , FeS _x , FeS _x or ZnS _x , wherein x =l~3.

The all-solid lithium ion battery provided by the third aspect of the embodiment of the present invention has a long cycle life and has excellent discharge capacity and rate performance.

The advantages of the embodiments of the present invention will be set forth in part in the description which follows. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graph showing the cycle performance test of an all-solid lithium ion battery of Example 1 and Comparative Example 1. The following is a preferred embodiment of the embodiments of the present invention, and it should be noted that those skilled in the art can make some improvements and retouching without departing from the principles of the embodiments of the present invention. These improvements and retouchings are also considered to be the scope of protection of the embodiments of the present invention.

A first aspect of the embodiments of the present invention provides an all-solid lithium ion battery composite electrode material, which solves the problem that a sulfide solid electrolyte easily reacts with an electrode active material to form a space charge layer, and between the electrode/solid electrolyte The interface creates a high impedance to lithium ion movement, resulting in a battery with lower output power, lower durability and cycling performance issues. A second aspect of the embodiments of the present invention provides a method for preparing an all-solid lithium ion battery composite electrode material. A third aspect of the embodiments of the present invention provides an all-solid lithium ion battery.

In a first aspect, an embodiment of the present invention provides an all-solid lithium ion battery composite electrode material, comprising an electrode active material and a coating layer disposed on a surface of the electrode active material, wherein the electrode active material is a positive electrode active material or The negative electrode active material, the material of the coating layer comprises, by weight: 0.1 to 20 parts of a polymer monomer and 0.1 to 50 parts of a polymer of a glycol derivative, 0.1 to 10 parts of a lithium salt, 0.1 to 10 a polymerization initiator and 50 to 99.9 parts of a plasticizer, wherein the polymer monomer is selected from the group consisting of a fluorine-based polymer monomer, an ether polymer monomer, an acrylic polymer monomer, and an acrylonitrile polymer monomer. One or several.

Compared with the prior art, the all-solid lithium ion battery composite electrode material provided by the present invention has a coating layer, which is coated as an interface modification layer on the surface of the electrode active material, and is not combined with the electrode active material. Reacts with a solid electrolyte. The coating layer coated on the surface of the electrode active material in the present invention can effectively inhibit the sulfide solid electrolyte S ₃ PS-SP ₃ center structure in an all-solid lithium ion battery as an intermediate layer of an electrode active material and a solid electrolyte. The crosslinked sulfur reacts with the electrode active material to decompose, suppresses the formation of the space charge layer, and suppresses the formation of high interfacial impedance, thereby not reducing the conductivity of lithium ions. The all-solid-state lithium-ion battery composite electrode material ultimately enables the battery to have a high output power, and has good durability and cycle stability.

The fluorine-based polymer monomer is vinylidene fluoride and/or vinylidene fluoride-hexafluoropropylene, the ether polymer monomer is ethylene oxide and/or propylene oxide, and the acrylic polymer monomer is sulfhydryl. Ethyl acrylate.

The ethylene glycol derivative is one or more selected from the group consisting of ethylene glycol monodecyl acrylate, ethylene glycol dimercapto acrylate, ethylene glycol acrylate, and ethylene glycol diacrylate.

The lithium salt is selected from lithium perchlorate LiC10 ₄ , lithium tetrafluoroborate LiBF ₄ , lithium hexafluorophosphate LiPF ₆ , lithium hexafluoroarsenate LiAsF ₆ , lithium trifluoromethanesulfonate LiCF ₃ S0 ₃ and bistrifluorodecylsulfonamide One or more of lithium LiN(CF ₃ S0 ₂ ) ₂ .

The polymerization initiator is selected from one or more of azobisisobutyronitrile, benzoyl peroxide, acetyl peroxide and dibenzophenone.

The plasticizer is selected from one or more of propylene carbonate, dinonyl carbonate, diethyl carbonate, ethyl ruthenium carbonate and ethylene carbonate.

The material of the coating layer further comprises 0.1 to 30 parts of an additive selected from the group consisting of nano-SiO ₂ , nano-Ti0 ₂ , nano-A1 ₂ 0 ₃ , single-walled carbon nanotubes, multi-walled carbon nanotubes, zeolite, and Mongolian Decalcification and molecular sieve One or several of ZSM-5. The addition of the nano-conductive material can improve the mechanical properties and ionic conductivity of the coating.

The positive electrode active material is selected from one or more of lithium cobaltate, lithium nickelate, lithium manganate, lithium iron phosphate, lithium nickel cobalt manganese oxide, vanadium pentoxide, molybdenum trioxide and titanium disulfide.

The negative active material is selected from one or more of graphite, hard carbon, silicon, silicon oxy-oxide, tin alloy, lithium cobalt nitride, lithium metal, and lithium alloy.

The thickness of the cladding layer may be from 0.1 to 2000 nm. The thickness of the coating layer in the present embodiment is 0.1 to 1000 nm. The side of the coating layer away from the electrode active material does not contain an electrode active material.

The all-solid lithium ion battery composite electrode material provided by the first aspect of the present invention can effectively inhibit the cross-linking sulfur in the central structure of the sulfide solid electrolyte S ₃ PS-SP _{3 from} reacting with the electrode active material to decompose Suppressing the formation of a space charge layer, suppressing the formation of a high interfacial impedance, thereby not reducing the conductivity of lithium ions; further, the cladding layer does not hinder the conduction of lithium ions between the electrode active material and the solid electrolyte; The all-solid lithium-ion battery composite electrode material finally enables the battery to have a high output power, and has good durability and cycle performance.

In parts by weight, 0.1 to 20 parts of polymer monomer, 0.1 to 50 parts of ethylene glycol derivative, 0.1 to 10 parts of lithium salt, 0.1 to 10 parts of a polymerization initiator, and 50 to 99.9 parts of a plasticizer are prepared. Obtaining a mixed solution, the polymer monomer being selected from one or more of a fluorine-based polymer monomer, an ether polymer monomer, an acrylic polymer monomer, and an acrylonitrile polymer monomer;

The mixed solution is disposed on the surface of the electrode active material by an electrospinning method, an electroblowing method, a liquid phase spraying method or a printing method by a thermal polymerization method, an electron beam polymerization method or an ultraviolet polymerization method. As a coating layer, an all-solid lithium ion battery composite electrode material is obtained.

The process of formulating the mixed solution further comprises adding 0.1 to 30 parts of an additive selected from the group consisting of nano-SiO ₂ , nano-TiO ₂ , nano-A _{1 2} _{3 3} , single-walled carbon nanotubes, multi-walled carbon nanotubes, and zeolite. One or more of montmorillonite and molecular sieve ZSM-5.

The thickness of the cladding layer may be from 0.1 to 2000 nm. In the present embodiment, the thickness of the coating layer is 0.1 to 1000 nm. The side of the coating layer away from the electrode active material does not contain an electrode active material.

The preparation method of the all-solid lithium ion battery composite electrode material provided by the second aspect of the present invention is simple and easy, and the integrated solid-state lithium ion battery composite electrode material can improve the electrode/solid state electricity. The de-synthesis interface reduces the impedance of lithium ions moving between the electrode active material and the solid electrolyte, so that the all-solid-state lithium ion battery has high output power, and has good durability and cycle performance.

The sulfide-based solid electrolyte of sulfide Li ₂ S and Li ₂ S in addition to the composition, the molar ratio of Li ₂ S and hazardous compound other than stone Li ₂ S 50: 50~95: 5.

The particle size of the powder of the sulfide-based solid electrolyte is 0.5 μηη! 〜 5μηι, more preferably, the particle diameter is 0.5 μΓη to 1 μηι.

The sulfide other than Li ₂ S is SiS ₂ , P ₂ S ₅ , B ₂ S ₃ , GeS ₂ , Sb ₂ S ₃ , ZrS _x , FeS _x , FeS _x or ZnS _x , wherein x=l~ 3.

The embodiments of the present invention are further described below in various embodiments. However, the embodiments of the present invention are not limited to the specific embodiments below. Changes may be implemented as appropriate within the scope of the unchanging primary rights.

Example 1

A method for preparing an all-solid lithium ion battery composite electrode material, comprising the following steps:

(1) 15 parts by weight of vinylidene fluoride, 20 parts of ethylene glycol monodecyl acrylate, 10 parts of lithium tetrafluoroborate LiBF ₄ , 5 parts of azobisisobutyronitrile and 50 parts of propylene carbonate Preparing a mixed solution;

(2) The mixed solution was connected to a stainless steel needle through a catheter, and the mixed solution was sprayed through the needle tube at a flow rate of 0.4 ml/h, using the electrode active material as a collecting body, and the vertical distance from the needle was 15 cm. Simultaneously grounding, connecting the needle tube to a high voltage generator, and adjusting the voltage to 15v, that is, the mixed solution is disposed on the surface of the electrode active material by electrospinning, and the electrode active material is lithium cobaltate;

Subsequently, in-situ polymerization was thermally initiated at 70 ° C, that is, a surface of the electrode active material was polymerized by thermal polymerization to form a coating layer having a thickness of 0.1 nm, and an all-solid lithium ion battery composite electrode material Al was obtained. The side of the coating layer away from the electrode active material does not contain the electrode active material Al.

Method for preparing all-solid lithium ion battery

(1) Preparation of Li ₂ SP ₂ S ₅ _^ glass-ceramic electrolyte

Li ₂ S and P ₂ S ₅ having a purity of 99.95% were added to a planetary mechanical ball mill at a mass ratio of 75:25, and ball-milled at room temperature for 10 hours, and then granulated by extrusion to prepare a particle size of 0.5~ 5 μηι particles, the spherical particles were heat treated at 360 ° C for 5 h, and then annealed to room temperature to obtain a Li ₂ SP ₂ S ₅ -based glass-ceramic electrolyte;

(2) assembling the composite electrode material A1 and the Li ₂ SP ₂ S ₅ _^ glass-ceramic electrolyte and the negative electrode active electrode prepared above into an all-solid secondary lithium battery, wherein the material of the negative electrode is graphite, and then aluminum plastic The film is packaged into a battery and chemically formed to obtain an all-solid lithium ion battery.

Example 2

(1) In terms of parts by weight, 15 parts of ethylene oxide, 0.1 part of ethylene glycol dimercapto acrylate, 0.1 part of lithium hexafluorophosphate LiPF ₆ , 10 parts of benzoyl peroxide, 50 parts of dinonyl carbonate and 0.1 parts by weight a portion of the nano Si0 _{2 is} prepared to obtain a mixed solution;

(2) The mixed solution is spun by a spinneret having an air nozzle, the spinning pressure is 5.88 χ 10 ⁵ Pa, and the voltage is 50 kV DC, that is, the mixed solution is set on the surface of the electrode active material by electrospinning. The electrode active material is lithium iron phosphate;

The solvent is then volatilized in a dry box and polymerized under UV irradiation (110W, λ=375 nm). As a coating layer of lOOOnm, an all-solid lithium ion battery composite electrode material A2 was obtained. The side of the coating layer away from the electrode active material does not contain the electrode active material A2.

The preparation method of the all-solid lithium ion battery is as described in Example 1, except that the all-solid lithium ion battery composite electrode material A2 obtained in the present embodiment is used.

Example 3

(1) In terms of parts by weight, 0.1 part by weight of decyl methacrylate, 15 parts of ethylene glycol acrylate, 10 parts of lithium hexafluoroarsenate LiAsF ₆ , 0.1 part of acetyl peroxide and 50 parts of ethylene carbonate are prepared. mixture;

(2) placing the mixed solution in a liquid plasma spraying system, the atomizing gas is nitrogen, the pressure is 0.7 MPa, the voltage is 40 V, and the current is 600 A, that is, the mixed solution is disposed on the surface of the electrode active material by liquid phase spraying. The electrode active material is graphite;

Subsequently, the solvent is evaporated in a drying oven, and polymerization is initiated by electron beam polymerization. The acceleration voltage is 200 KV, the processing speed is 5 m/min, and the irradiation width is 20 cm, that is, the surface of the electrode active material is polymerized by electron beam polymerization to a thickness of 2000 nm. The cladding layer is used to produce an all-solid lithium ion battery composite electrode material A3. The side of the coating layer away from the electrode active material does not contain the electrode active material A3.

The preparation method of the all-solid lithium ion battery is as described in Example 1, except that the all-solid lithium ion battery composite electrode material A3 obtained in the present embodiment is used.

Example 4

(1) 10 parts by weight of vinylidene fluoride and 10 parts of propylene oxide, 50 parts of ethylene glycol diacrylate, 5 parts of trifluoromethyl group, lithium LiCF ₃ S0 ₃ , 5 parts of diphenyl hydrazine Ketone, 50 parts diethyl carbonate and 30 a single layer of carbon nanotubes, prepared to obtain a mixed solution;

(2) The mixed solution is disposed on the surface of the electrode active material by a printing method, and the electrode active layer has a thickness of 100 nm to prepare an all-solid lithium ion battery composite electrode material A4. The side of the coating layer away from the electrode active material does not contain the electrode active material A4.

The preparation method of the all-solid-state lithium ion battery is as described in Example 1, except that the all-solid lithium ion battery composite electrode material A4 obtained in the present embodiment is used.

Example 5

(1) 10 parts by weight of vinylidene fluoride-hexafluoropropylene and 5 parts of decyl decyl acrylate, 5 parts of ethylene glycol monodecyl acrylate and 5 parts of ethylene glycol dimercaptoacrylate, 5 parts of lithium bis(trifluorodecyl)amide, LiN(CF ₃ S0 ₂ ) ₂ , 2.5 parts of azobisisobutyronitrile and 2.5 parts of benzophenone, and 99.9 parts of ethyl cesium carbonate, and 10 parts of zeolite. Preparing a mixed solution;

(2) The mixed solution was connected to a stainless steel needle through a catheter, and the mixed solution was sprayed through the needle tube at a flow rate of 0.4 ml/h, using the electrode active material as a collecting body, and the vertical distance from the needle was 15 cm, and the grounding was The needle tube is connected to a high voltage generator, and the voltage is adjusted to 15v, that is, the mixed solution is disposed on the surface of the electrode active material by electrospinning, and the electrode active material is molybdenum trioxide;

Subsequently, the solvent was evaporated in a dry box, and a polymerization layer (110 W, λ = 375 nm) and a coating layer of 50 nm were initiated under ultraviolet light irradiation to obtain an all-solid lithium ion battery composite electrode material A5. The side of the coating layer away from the electrode active material does not contain the electrode active material A5.

The preparation method of the all-solid lithium ion battery is as described in Example 1, except that the all-solid lithium ion battery composite electrode material A5 obtained in the present embodiment is used. Ratio 1

The commercially available uncoated electrode active material lithium cobalt oxide (LiCo0 ₂ ) is assembled into an all-solid lithium ion battery, wherein the material of the negative electrode is graphite, and the solid electrolyte is the Li ₂ SP ₂ S ₅ based glass-ceramic electrolyte obtained in Example 1. .

Effect embodiment

In order to strongly support the beneficial effects brought by the technical solutions of the embodiments of the present invention, the following cyclic capacity performance tests are provided:

The all-solid-state lithium ion battery assembled in Example 1 and Comparative Example 1 was subjected to a charge and discharge test at a voltage of 3.0 to 4.4 V at 0.5 C, and the test results are shown in Fig. 1. It can be seen from the figure that the lithium cobalt oxide (LiCo0 ₂ ) coated by the coating has a capacity retention rate of 87.7% after 600 cycles, while the uncoated lithium cobalt oxide (LiCo0 ₂ ) passes through. After 600 cycles, the capacity retention rate was only 80.0%. It can be seen that the cycle performance of the coated lithium cobalt oxide (LiCo0 ₂ ) was significantly improved.

Claims

Rights request

1. An all-solid-state lithium-ion battery composite electrode material, characterized in that it includes an electrode active material and a coating layer provided on the surface of the electrode active material, and the electrode active material is a positive electrode active material or a negative electrode active material, The materials of the coating layer include, in parts by weight: a polymer formed from 0.1 to 20 parts of polymer monomer and 0.1 to 50 parts of ethylene glycol derivatives, 0.1 to 10 parts of lithium salt, 0.1 to 10 parts of polymerization initiator agent and 50 to 99.9 parts of plasticizer, the polymer monomer is selected from one of fluorine polymer monomers, ether polymer monomers, acrylic polymer monomers and acrylonitrile polymer monomers Or several.

2. An all-solid-state lithium-ion battery composite electrode material according to claim 1, characterized in that the fluorine polymer monomer is vinylidene fluoride and/or vinylidene fluoride-hexafluoropropylene, ether The polymer monomer is ethylene oxide and/or propylene oxide, and the acrylic polymer monomer is methyl methacrylate.

3. An all-solid-state lithium-ion battery composite electrode material as claimed in claim 1, characterized in that the ethylene glycol derivative is selected from the group consisting of ethylene glycol monomethacrylate and ethylene glycol dimethacrylate. One or more of ester, ethylene glycol acrylate and ethylene glycol diacrylate.

4. An all-solid-state lithium-ion battery composite electrode material as claimed in claim 1, characterized in that the material of the coating layer further includes 0.1 to 30 parts of additives, and the additives are selected from nano-SiO ₂ , One or more of nano Ti0 ₂ , nano A1 ₂ 0 ₃ , single-walled carbon nanotubes, multi-walled carbon nanotubes, zeolite, montmorillonite and molecular sieve ZSM-5.

5. An all-solid-state lithium-ion battery composite electrode material as claimed in claim 1, characterized in that the thickness of the coating layer is 0.1~2000nm.

6. The all-solid-state lithium-ion battery composite electrode material according to claim 1, wherein the side of the coating layer away from the electrode active material does not contain the electrode active material.

7. A method for preparing composite electrode materials for all-solid-state lithium-ion batteries, which is characterized by including: Following steps:

In parts by weight, take 0.1 to 20 parts of polymer monomer, 0.1 to 50 parts of ethylene glycol derivatives, 0.1 to 10 parts of lithium salt, 0.1 to 10 parts of polymerization initiator and 50 to 99.9 parts of plasticizer, and prepare A mixed solution is obtained, wherein the polymer monomer is selected from one or more types of fluorine polymer monomers, ether polymer monomers, acrylic polymer monomers and acrylonitrile polymer monomers;

The mixed solution is disposed on the surface of the electrode active material through thermal polymerization, electron beam polymerization or ultraviolet polymerization to form a coating through electrospinning, electroblowing spinning, liquid phase spraying or printing. layer to prepare an all-solid-state lithium-ion battery composite electrode material.

8. A method for preparing an all-solid-state lithium-ion battery composite electrode material according to claim 7, characterized in that the fluorine polymer monomer is vinylidene fluoride and/or vinylidene fluoride-hexafluoropropylene , the ether polymer monomer is ethylene oxide and/or propylene oxide, and the acrylic polymer monomer is methyl methacrylate.

9. The method for preparing a composite electrode material for an all-solid-state lithium-ion battery according to claim 7, wherein the ethylene glycol derivative is selected from the group consisting of ethylene glycol monomethacrylate, ethylene glycol dimethacrylate, and ethylene glycol dimethacrylate. One or more of methacrylate, ethylene glycol acrylate and ethylene glycol diacrylate.

10. An all-solid-state lithium-ion battery, including a positive electrode, a negative electrode and a sulfide-based solid electrolyte. The positive electrode or negative electrode includes the all-solid-state lithium-ion battery composite electrode material described in claim 1.